Remove allow unused from gpui2, vim2 tests and terminal_view2 (#3813)

Release Notes:

- N/A

crates/vim2/src/test/neovim_backed_binding_test_context.rs

@@ -1,6 +1,3 @@
-#![allow(unused)]
-// todo!()
-
 use std::ops::{Deref, DerefMut};
 
 use crate::state::Mode;

crates/vim2/src/test/neovim_backed_test_context.rs

@@ -1,8 +1,5 @@
-#![allow(unused)]
-// todo!()
-
 use editor::{scroll::VERTICAL_SCROLL_MARGIN, test::editor_test_context::ContextHandle};
-use gpui::{point, px, rems, size, Context};
+use gpui::{px, size, Context};
 use indoc::indoc;
 use settings::SettingsStore;
 use std::{

crates/vim2/src/test/vim_test_context.rs

@@ -1,6 +1,3 @@
-#![allow(unused)]
-// todo!()
-
 use std::ops::{Deref, DerefMut};
 
 use editor::test::{